Multi-element pneumatic actuator



Ma 30, 1967 E, Jews 3,322,255

MULTI-ELEMENT PNEUMATIC ACTUATOR Filed Jan. 24, 1966 'thin tapes as described in United States Patent MULTI-ELEMEN T This simple and inexpensive actuator mechanism is particularly suited for driving a number of independently operable, closely adjacent devices, such as typewriter keylevers.

Key operated mechanisms such as typewriters, pianos, etc., are often automated by the provision of individual actuators to operate the several keylevers in response to record data. .Wherever a large number of keys are involved, the manufacturing and assembly cost of the individual actuators becomes a significant consideration. Electromechanical actuators, such as solenoids, have been employed but are relatively expensive. Traditionally, player pianos and automatic typewriters have employed pneumatic-mechanical transducers as a low cost alternative to solenoid actuators.

Transduction of a pneumatic signal into an actuating force is accomplished most efiiciently by an expansible chamber motor. Such motors conventionally appear as piston cylinder units, diaphragms, and bellows. Recently, U.S. patent application Ser. No. 421,032, entitled, Monostable Fluid Logic Element and Actuator, filed Dec. 24, 1964, by William F. Voit, Jr., have been proposed to provide a novel version of an expansible chamber motor that is characterized by a very fast response due to the extremely low mass of the moving tape member.

Where space is at a premium, as in typewriters having plural keylevers spaced on standard inch centers and having positive limitations on vertical machine height, it is difficult to integrate totally independent actuators into existing design limitations.

Accordingly, an object of my invention has been to devise a machine operator that is particularly suited for operation of individual. load devices located in a closely confined space.

Another object of my invention has been to devise an operator of simple construction having adequate reliability and operating speed to drive moderate load devices while maintaining an eflicient materials andassembly cost. A

While the objects of my invention are directed to an actuator bank for operating a plurality of closely adjacent members, attention is called to application Ser. No. 522,613 entitled, Pneumatic Actuator, filed by J, C. Lambiotte on Jan. 24, 1966, the objects of which are directed to an individual pneumatic actuator for use where space between specific operated mechanisms is less significant.

One phase of my invention involves the provision of a plurality of closely adjacent flexible tape members, each forming an independent loop. All loops are held between common parallel sidewalls and define boundary portions of individual expansible chambers therewithin. The single pair of sidewalls define further portions of the chamber boundaries. The individual loops can be spaced as close together as any independently operable mechanical devices which they may be required to operate. The chambers formed by the individual loops arepressurized from independent fluid signals, and expand when pressurized to occupy the space of several adjacent unexpanded loops. The efiicient use of the available space is thus apparent.

These and other objects, features, and advantages of my invention will be apparent to those skilled in the art upon reading the following more specific description of Patented May 30, 1967 a preferred embodiment of my invention wherein specific reference is made to the accompanying drawings, of which:

FIGURE 1 is a partial perspective view of a portion of a typewriter, assembled with an operator constructed in accordance with a preferred embodiment of my invention;

FIGURE 2 is a front vertical cross-sectional view of the operator shown in FIGURE 1 taken along lines IIII thereof; and

FIGURE 3 is a front vertical cross-sectional view similar to that of FIGURE 2, but showing a modified version of my invention.

Referring now more specifically to the drawings, in

FIGURES 1 and 2 there is shown a keyboard operator or actuator bank 10, including a plurality of independent, flexible actuator tape loops 11, Each loop 11 is connected in a force transmitting relationship by its inner surface portion 12 (FIGURE 2) to an individual keylever 21 of a typewriter 20, such as that disclosed in U.S. Patent 2,919,002, entitled, Selection Mechanism for a Single Printing Element Typewriter, issued to L. E. Palmer, Dec. 29, 1959. The keylevers or independently operable load devices 21 are biased upwardly to their non-operated position by leaf springs 22 that engage tail portions 23 thereof. Each keylever operates an associated print character selection interposer 24. The keylevers 21 are closely spaced to provide a compact keyboard for manual opera tion. The spacing between adjacent key levers usually is a standard inch between centers.

r The tape loops 11 are suspended between a pair of substantially parallel side walls 13 that are spaced a distance 14 substantially equal to the width of the tape loops 11 as defined by their parallel side edges 15 to form an effective fluid seal. Each tape loop thus provides a movable wall defining a portion of an expansible chamber boundary. A top wall or reaction member 16 is supported between the side walls 13 and is formed with individual restricted slots 17 for receiving the tape loops 11. The edges of slots 17 engage laterally opposed outer surface portions of the tape loops 11 to form an effective seal there'between to indirectly enclose the chamber boundary portion defined by the loops and thereby create an effectively closed pressurizeable expansible chamber 18 within each loop.

A plurality of independent signal input conduits or inlets 31, for receiving superambient pressure fluid, are individually associated with the tape loops 11 for creating an actuating pressure within a selected expansible chamber 18. The input conduits 31 each have an extension 32,

projecting into the associated tape loops 11 to prevent misalignment therebetween which could cause a malfunction. The conduits 31 are controlled by any convenient data input device, such as selectively activatable springbiased key valves 33. A selected chamber 18 expands from its normal position, sho-Wn in full lines, causing a sufliciently that upon termination of a pressure signal,

residual pneumatic forces are dissipated and the spring 22 restores the associated keylever 21 and the tape loops 11 to their original or normal positions.

A modified operator 40 according to my invention is shown in FIGURE 3. Independent flexible tape loops 41 are formed from elongated strips anchored at one end 42 to a stationary top wall or reaction member 43 of the operator and connected to keylevers 21 at their other ends 44 by rivets 45. A pair of parallel side walls (not shown) like 13 of FIGURE 1, form expansible, pressurizea'ble chambers 46 within the tape loops 41. Signal fluid is introduced by conduits 47 conveniently formed in the stationary top wall 43, and which extend within the tape loops 41. The inner surface 48 of the tapes 15 slidably engages the edges of slot 49 in the top wall 43 which directly encloses the boundary portion of the chambers 46 defined by the tape loops 41.

This modification of my invention has the advantage of requiring lower friction to provide a sealed chamber, but has the disadvantage of generating only half as much force per unit volume change. Also, it is somewhat more difficult to assemble than the embodiment shown in FIG- URES 1 and 2. Operation, however, is the same in that pressurization of an expansible chamber 46 causes inflation as shown in the broken lines and takes advantage of the flexibility of its neighbors to achieve compactness inherent to my invention.

Those skilled in the art will recognize that I have provided a particularly simple and inherently compact machine operator or actuator bank that is particularly suited for operating a plurality of closely adjacent mechanical members.

While some specific preferred embodiments have been shown herein for purposes of illustration, and in com pliance with statutory requirements, it will be understood that modifications, deletions, and additions can be made without departing from the scope and spirit of my invention as defined by the appended claims.

I claim:

1. An operator for a plurality of independently operable load devices and including a plurality of operably independent, pressurizeable, expan-sible boundary chambers and fluid inlet means coperating therewith, wherein the improvement comprises:

a plurality of independent flexible tapes, each defining a loop having a surface portion bounded by substantially parallel side edges and each defining a portion of one of the chamber boundaries,

means for operatively connecting each of said tapes in force transmitting relationship to respective ones of said plurality of load devices,

a pair of substantially parallel sidewalls common to all said tape loops and embracing the side edges thereof, said pair of sidewalls forming additional portions of the chamber boundaries, and

a stationary reaction member slidably engaging said surface portion of each of said tape loops to enclose the chamber boundary portion defined thereby.

2. An operator as defined in claim 1 wherein the fluid inlet means include the further improvement which comprises individual conduits associated with each of said loops and projecting into the interior thereof to prevent disorientation of said loops relative to said conduits.

3. An operator as defined in claim 1 wherein each of said loops have a normal position when not pressurized and an expanded position when pressurized, the spacing between adjacent loops being sufliciently small that each loop, when in its expanded position, deflects at least one adjacent loop from its normal position.

4. An operator as defined in claim 1 wherein each of said loops is formed of a strip having opposed ends, one of said opposed ends of each strip being secured to said reaction member.

5. A machine having independently operable load devices in combination with an operator therefor, said operator including a plurality'of operably independent pressurizeable, expansible boundary chambers, wherein the improvement comprises:

a plurality of independent flexible tapes each defining a loop having a surface portion bounded by substantially parallel side edges and each defining a portion of one of the chamber boundaries, each of said tape loops being operatively connected in force transmitting relationship to respective ones of said plurality of load devices,

a pair of substantially parallel side walls common to all said tape loops and embracing the side edges thereof, said pair of sidewalls forming addiitonal portions of the chamber boundaries,

a stationary reaction member slidably engaging said surface portion of each of said tape loops to enclose the chamber boundary portion defined thereby, and

selectively activatable means for creating a fluid pressure within each of said chambers that is greater than the pressure outside thereof.

6. A machine as defined in claim 5 wherein said independently operable load devices comprise character print selection means of a typewriter.

7. A machine as defined in claim 6 wherein each of said loops have a normal position when its associated pressurizing means is inactive and an expanded position when its associated pressurizing means is active, the spacing between adjacent loops being sufficiently small that each loop, when in its expanded position, deflects at least one adjacent loop from its normal position.

References Cited UNITED STATES PATENTS 848,207 3/1897 Rodesch 84 -29 1,003,279 9/1911 MacArthur 84-50 1,005,793 10/ 1911 Atkinson 84-50 1,842,883 1/1932 Swanson 197-19 2,795,668 6/1957 Puckett 200-81 2,991,763 7/1961 Marette 92-89 X ROBERT E. PULFREY, Primary Examiner.

E. S. BURR, Assistant Examiner. 

1.AN OPERATOR FOR A PLURALITY OF INDEPENDENTLY OPERABLE LOAD DEVICES AND INCLUDING A PLURALITY OF OPERABLY INDEPENDENT, PRESSURIZEABLE, EXPANSIBLE BOUNDARY CHAMBERS AND FLUID INLET MEANS COPERATING THEREWITH, WHEREIN THE IMPROVEMENT COMPRISES: A PLURALITY OF INDEPENDENT FLEXIBLE TAPES, EACH DEFINING A LOOP HAVING A SURFACE PORTION BOUNDED BY SUBSTANTIALLY PARALLEL SIDE EDGES AND EACH DEFINING A PORTION OF ONE OF THE CHAMBER BOUNDARIES, MEANS FOR OPERATIVELY CONNECTING EACH OF SAID TAPES IN FORCE TRANSMITTING RELATIONSHIP TO RESPECTIVE ONES OF SAID PLURALITY OF LOAD DEVICES, A PAIR OF SUBSTANTIALLY PARALLEL SIDEWALLS COMMON TO ALL SAID TAPE LOOPS AND EMBRACING THE SIDE EDGES THEREOF, SAID PAIR OF SIDEWALLS FORMING ADDITIONAL PORTIONS OF THE CHAMBERS BOUNDARIES, AND A STATIONARY REACTION MEMBER SLIDABLY ENGAGING SAID SURFACE PORTION OF EACH OF SAID TAPE LOOPS TO ENCLOSE THE CHAMBER BOUNDARY PORTION DEFINED THEREBY. 